1. Field of the Invention
This invention relates to an improved system for supplying conditioned air through duct means to an area to be treated by the conditioned air and to a method of making the same as well as to a thermostat for such a system or the like.
2. Prior Art Statement
It is known to provide a system for supplying conditioned air through duct means to an area to be treated by the conditioned air, the system comprising an area thermostat that tends to maintain the temperature of the area at a selected set point temperature of the thermostat and having means providing a pneumatic signal in relation to the temperature sensed by the thermostat, a pneumatically operated damper means for controlling the flow of air from the duct means to the area, a controller having means for directing a pneumatic signal to the damper means to operate the same in relation to the pressure of the pneumatic signal of the thermostat and in relation to the air pressure in the duct means to compensate for pressure changes originating elsewhere in the system whereby the controller tends to maintain the air flow to the area at the rate called for by the pneumatic signal of the thermostat regardless of the air pressure in the duct means, and adjustable maximum and minimum air flow rate setting devices for selecting the air flow rate range of the air flow from the duct means to the area under the control of the controller.
For example, see the prior art system depicted in FIG. 1 of this application.
It can be seen that the maximum and minimum air flow rate setting devices of the prior known system of FIG. 1 are disposed in the controller which is mounted in the ceiling of the building containing the system and do not change the pressure range of the pneumatic signal produced by the thermostat.